Offence sells tickets, defence wins games, and special teams win championships, goes the old sports adage. “Special teams” are comprised of players sent on-field or on-ice during special moments in a game like during a power play in ice hockey, when the opposing team must play short a player or two due to a penalty.

The power play in ice hockey is especially revered as it’s regarded as a golden opportunity to score goals in what is generally a low-scoring game. It has been National Hockey League policy lately to call more penalties, both to release star players from illegal plays that slows them down, and to help increase scoring, seen by the league as a key selling feature in newer markets where the finer points of the game are not appreciated.

So far this year, the average number of goals scored per game by each team is about 2.8, with only about a 14% variation between top scoring and bottom scoring teams. The average number of power play goals per game for each team is around 0.8, which shows how important power play goals are: they account for over 28% of all goals a team gets. Consequently, teams focus on power play opportunities, fans get especially excited when they come along, and the league’s commissioner is pleased.

But does the power play really provide more of a scoring opportunity than regular five-on-five play? The question seems absurd to ask, for how can a team with five players on the ice not gain an advantage over a team only allowed to put four players on the ice? But the statistics show the power play may not provide the scoring advantage everyone assumes it does.

Teams enjoy roughly 14 minutes of power play time per game on average, out of a total of about 62.5 minutes that make up the average game (60 minutes of regulation time plus all or part of five extra minutes in the case of a tie at the end of 60 minutes). They also play about 14 minutes of shorthanded hockey. This leaves only about 32.5 minutes of even strength hockey per game—barely over 50%.

On average, teams score about one goal for every 17.5 minutes of power play time. But they score two even-strength goals in the remaining 32.5 minutes, or about one goal for every 16.25 minutes of even strength time. This surprising fact shows that every power play minute generates about 8% fewer goals than every even strength minute, suggesting that power plays actually confer a slight disadvantage.

This is despite the fact that common coaching strategies dictate that for even strength time, a coach seeks to distribute scoring players among at least three lines, while for power play minutes, a coach will concentrate his best scoring players onto two specially composed power play lines. Some coaches even remove a defenceman from the ice and field four scoring forwards. Even using that increased potency, power play minutes are less effective than even strength minutes at generating goals.

Top scorers on average play 21 minutes per game. They typically play about nine minutes in power play time and about 12 minutes in even strength time. If we look at the individual even strength statistics of players typically comprising the top power play line, we find they generate between them a goal for every 12 minutes of even strength time. That is to say, however counterintuitive it might appear, players that comprise the top power play lines on average produce 25% more goals during their even strength minutes than they do during their power play minutes. The power play, in this analysis, would appear to confer a serious disadvantage particularly for top scorers.

Of course, a coach cannot use his top five scorers during all sixty or so minutes of a game, and nor can a general manager put together a team roster filled top to bottom with top scoring players. Even top scoring players must rest for roughly two thirds of a game during which a coach must use lesser-scoring players. And, of course, a goal prevented is worth the same as a goal scored, so a coach must think about icing players good at stopping opposition goals as much as he thinks about icing players good at scoring goals. And he must spread out his goal scorers to prevent the opposition from playing hard defensively only against one key line.

But if a coach is keen to get a goal in any minute, he is more likely to see one if he puts his top power play line out on the ice in any even strength minute he chooses than he is even when he puts the same line out in a power play minute.

There is, however, one definite advantage to a power play: the chances of being scored on while enjoying a one or two player differential on the ice drops way down compared to even strength time. Teams on average allow one goal against for every 130 minutes of power play time compared to a goal against for every 16.25 minutes of even strength time. Thus, while the power play is commonly regarded as a key offensive moment for teams by fans, players and coaches alike, it’s real advantage lies in its potential as a key defensive moment. A team that causes its opposition to take more penalties gains an advantage not from scoring more on its ensuing power play but from preventing its opposition from scoring for those two minutes.

However, the expectation of fans is that a penalty should cost a team more than that. This analysis shows that all a penalty really does is prevent a team from scoring for two minutes, a fairly unlikely event in any case. For a team enjoying a lead in a game, there is virtually no reason to avoid taking penalties—and lots of reasons to risk them, including the ability to intimidate other teams with illegal hits. Indeed, though penalty minutes taken by teams vary from nearly 19 minutes by Anaheim to only a little over 11 by Detroit, penalty minutes provide no predictor of success for teams. Anaheim is highly successful this year and won the Stanley Cup last year when it also lead the league in penalty minutes, while Detroit leads the league this year while being the least penalized team.

League rules offer three key concessions to penalized teams that might account for why penalties do not cost a team in goals scored against, and why so many players and coaches don’t try hard enough to avoid play that is illegal. Teams called for illegal play do not suffer a penalty if the opposition scores a goal before the offending team touches the puck causing the referee to blow the whistle and stop play. Worse, penalized players do not have to serve the full two minute penalty if the opposition scores during their power play. And worse still, shorthanded teams are allowed to “ice” the puck—that is, they are allowed to shoot the puck from their own end all the way down to the other end of the rink, a play that would result, in even strength time, in a whistle stopping play, a face off back in the offender’s zone, and a ban against the offending team changing players, meaning they must leave tired players on the ice.

If the league forced players to serve their penalties even if the opposition scores before the offending team next touches the puck, and if players had to serve their full two minutes even if the opposition scores on their power play, and if the icing rule still applied even to penalized teams, power play minutes would likely become more effective scoring moments than even-strength minutes, guaranteeing that coaches and players would try harder to avoid the illegal and dangerous plays that result in penalties.

These changes, rather than new rules and more stringent enforcement of them—which is the strategy the league has been pursuing—would result in the more open, free-flowing and higher-scoring games that all fans and the commissioner want to see. With already nearly half the average game spent in power play minutes for one or the other team, more rules and more penalties will never produce more scoring, but will only prevent more scoring—which is directly contrary to the stated wishes of league officials—and at the same time will do nothing to prevent illegal play that slows down star players and injures them.